Refractory roof and method



Sept- 5 c. E. GRIGSBY 3,340,832 REFRACTORY ROOF" AND METHOD Filed April 22, 1966 5 Sheets-Sheet 1 IN VEN TOR. CAZJ/er A? rajdi/ ATTORNEYS P 12, 1957' I c. E. GRIGSBY I 3,340,832

REFRACTORY ROOF AND METHOD Filed April 22, i966 5 Sheets-Sheet i3 azz.

'V Vff N TOR ATTORNEYS p 1967 c. E. GRIGSBY 3,340,832

REFRACTORY ROOF AND METHOD Fiied April 22, 1966 5 Sheets-Sheet s i 77 dw/er 5 g??? 1 m Dank ATTORNEYS Sept. 12, 1967 v c. E. GRIGSBY 3,340,832

' I REFRACTORY ROOF AND METHOD Filed April 22, 1966 I 5 Sheets-Sheet 4 r4 l l I 1 j; 22

ff "Z z ATTORN EYS United States Patent Oil-ice 334M832 Patented Sept. 12, 1967 vania Filed Apr. 22, 1966, Ser. No. 544,618 23 Claims. (Cl. 110-99) ABSTRACT OF THE DISCLOSURE The invention relates to a refractory roof and a process in which ferrous metal corset plates extend in sets across the cold ends of refractory brick and support hangers, the corset plates being secured to hold-down beams, the corset plates at their opposite ends and remote from the cold ends having recesses through which the hold-down beams extend. The anchoraging of the hold-down beams to the corset plates may be by tension members extending over the beams. Flowing air against the cold ends of the brick may remove dust. The corset plates may have feet which engage the cold ends.

Description of the invention The present application is a continuation-in-part of my copending application Ser. No. 516,236, filed Dec. 27, 1965, for Refractory Roof and Method.

The present invention relates to basic refractory roofs for furnaces, especially metallurgical furnaces such as open hearth (Siemens) furnaces, electric arc furnaces and the like and to methods of erecting them.

A purpose of the invention is to avoid localized hot areas under the hold-down beams in metallurgical furnace roofs.

A further purpose is to facilitate removal of dust and and dirt on metallurgical furnace roofs.

A further purpose is to increase the life of a metallurgical furnace roof.

A further purpose is to facilitate the separation of worn out roof brick from corset plates and beams in re-roofing.

A further purpose is to facilitate installation of new basic refractory roofs.

A further purpose is to provide a plurality of basic refractory brick arranged side by side, each having a hot end and a cold end and including hanger attachments at the cold ends of at least some of the brick, ferrous metal corset plates, preferably of steel, in sets extending transversely of the roof, each set including corset plates arranged end to end and preferably overlapped, in contact with and terminating at the cold ends of the brick and extending above the cold ends of the brick generally at a right angle thereto, the corset plates having a height at right angle to the cold ends at least six times their thickness, steel supporting structure including longitudinal hold-down beams above the cold ends of the brick, fastenings between the ends of the corset plates and the holddown beams to support the corset plates, and hangers from the corset plates to the hanger attachments, the corset plates at their opposed ends and remote from the cold ends of the brick having recesses, through which the holddown beams extend, engaging the bottoms of the recesses and thus spacing the hold-down beams from the cold ends.

A further purpose is to provide for overlapping of the ends of the corset plates at the point at which they are recessed beneath the hold-down beams so that the corset plates will adequately support the holdadown beams in spaced relation to the cold ends of the brick notwithstanding variations in position of one corset plate with respect to the adjoining one due to variation in distance between hold-down beams.

A further purpose is to provide tension members as fastenings from the ends of the corset plates across the tops of the hold-down beams, extending the tension members over the beams in contact therewith and securing them at the ends to the corset plates as by bending to engage in holes, welding, riveting, clamping, bolting or any other suitable fastening means.

A further purpose is to take advantage of the improved construction to facilitate cleaning by blowing air transversely on the furnace roof to avoid or periodically remove dust accumulation.

A further purpose is to provide feet on the corset plates so that the roof can be erected by erecting a form, placing the brick in position for the arch on the form, positioning the corset plates in sets end to end or preferably overlapped across the roof, standing upright on the brick, terminating at the brick, and held upright by their feet, with recesses at the abutting or preferably overlapping ends of the corset plates in line transversely of the furnace, positioning steel supporting structure above the corset plates including hold-down beams running longitudinally, inserted from above in the recesses, resting on the bottom of the recesses above the brick, cross-connecting each abutting or overlapping corset plate to the other above and in contact with the top of the hold-down beam, and connecting hangers from suitable hanger tabs or abutments on the brick (or on certain brick) to the tops of the corset plates, the corset plates having a deep narrow section except at the feet.

A further purpose is to provide pairs of directly opposed feet at the same position along the length of the corset plate, and to locate the pair of opposed feet preferably at the middle of the corset plate but permissibly distributed at a plurality of points along the corset plate such as /6, /2 and of the length of the corset plate, or near the opposite ends thereof.

A further purpose is to employ feet of unequal lengths.

A further purpose is to make the feet with lateral openings through which air can circulate.

A further purpose is to clear the feet from engagement with the cold ends except at points remote from the corset plates, and preferably to engage the cold ends by hearing plates near the ends of the feet.

A further purpose is to cross brace the feet from two corset plates A further purpose is to interpose sprung arch bricks among suspended brick and to hold down the sprung arch brick by spacers between the cold ends and the bottom of the hold-down beams or by extending the feet to engage the cold ends of the sprung arch brick, or by both expedients.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate a few only of the numerous embodiments in which the invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a perspective of a furnace roof embodying the invention.

FIGURE 2 is an enlarged vertical section through a modified roof of the invention parallel to the plane of one set of corset plates.

FIGURE 3 is a view similar to FIGURE 2 showing a modification in which the ends of the tension bars are secured to the corset plates by welding only.

FIGURE 4 is a view similar to FIGURE 2 in which the tension bars are rods hooked into holes in the corset plates at the ends.

FIGURE 5 is a fragmentary section of a corset plate having directly opposed feet which have lateral openings and contact the cold ends of the brick only at points remote from the corset plate.

FIGURE 6 is a view similar to FIGURE 5, showing a modification having a bearing plate near the outer end of each foot.

FIGURE 7 is a view similar to FIGURE 6 showing a modification in which the foot is suported from two adjoining corset plates.

FIGURE 8 is a view similar to FIGURE 5 of a modification in which the feet have blunt outer ends.

FIGURE 9 is a fragmentary top plan view of a corset plate having a pair of directly opposed feet only at the middle.

FIGURE 10 is a top plan view of a corset plate having opposed pairs of feet distributed along the length.

FIGURE 11 is a top plan view of a corset plate having opposed pairs of feet distributed at points corresponding to /3 and 73 of the length.

FIGURE 12 is a top plan view of a corset plate having opposed pairs of feet near the ends.

FIGURE 13 is a longitudinal section of a fully suspended roof according to the invention.

FIGURE 14 is a longitudinal section of a partially suspended and partially sprung roof according to the invention.

FIGURE 15 is a view similar to FIGURE 14 showing a modification.

In the prior art good results have been obtained with a basic refractory roof construction for metallurgical furnaces such as open hearth (Siemens) steel furnaces, and the like using corset plates having a deep thin section interposed between transverse rows of brick and extending above the cold ends of the brick often to support hangers connected to some or all of the brick. This is subject to the serious disadvantage that the corset plates are destroyed during each campaign of the furnace. Further construction of this roof required both bricklayers and steel construction men, complicating the operation considerably. A modification was developed (Grigsby US. Patent No. 3,093,099) in which the corset plates rest on the cold ends and terminate at them, the corset plates at their ends being connected to hold-down beams which extend longitudinally and also rest on the cold ends of the brick.

While the improvement just mentioned has many advantages, it has in turn led to some difficulties which the present invention seeks to overcome. There has been a tendency to develop localized hot areas under the holddown beams which have caused premature failure of some roofs. Study of these failures has shown that the contact of the hold-down beams directly with the cold ends of the brick prevents cooling the brick by air at these points and the metallic cooling by the beams has not been an adequate substitute. Furthermore, the holddown beams have tended to trap dirt and dust causing mounds which impair heat transfer from the roof to the air above.

The consequence has been failure of refractory by premature spalling, melting and distortion of hold-down beams and destruction of corset plates.

The prior art construction under discussion is expensive to disassemble when re-roofing is required. It requires unbolting or unscrewing of fastenings above the roof before the old roof can be dropped to the furnace floor and building of forms for the new roof can begin.

In accordance with the present invention, the advantages of the prior art constructions just referred to are maintained, by providing corset plates located entirely above the cold ends of the brick and securing hold-down beams and corset plates together so that the refractory bricks are anchored against movement vertically either downwardly or upwardly, but the difliculties encountered in the prior art constructions are avoided.

The corset plates terminate as before at the cold ends of the refractory bricks. As before, they are directly in contact to the hold-down beams. Unlike the prior art construction, however, the corset plates at the abutting or preferably overlapping ends extend in under the holddown beams and have recesses in line with the holddown beams. When it is said that the corset plates extend in prolongation of one another, it is contemplated that they will preferably overlap at the ends.

The hold-down beams extend through these recesses and rest on the bottoms of the recesses so that they are raised above the cold end and air is free to circulate under them and dust and dirt cannot accumulate against the hold-down beams to promote the occurrence of localized hot areas in the roof.

The hold-down beams can preferably be inserted after the corset plates are in place, and with this purpose the corset plates are made capable of standing upright by themselves as by lateral feet which engage the cold ends of the brick, but they are in contact with the hold-down beams. To secure the corset plates against moving downward, tension members, suitably tension bars, are provided, which extend across in contact with the tops of the hold-down beams and are secured to the corset plates at the opposite ends as by hooking them into openings in the corset plates, welding them to the corset plates for bolting, clamping or riveting them to the corset plates or any combination of these. The corset plates are held against upward movement because their ends at the bottoms of the recesses engage the bottoms of the holddown beams, and they are held against downward movement as just stated because the tension members secured to them extend across and in contact with the tops of the hold-down beams.

Once the roof has completed its campaign, the invention lends itself very etfectively to building a new roof. It is only necessary to cut the tension members with a cutting torch in order to cause the refractory and the corset plates to drop. The corset plates can then be separated from the brick and removed for reuse. It is only necessary to remove any residual portions of the tension members, in order to use the corset plates on a new roof. The quick removal of the old roof allows the early construction of the forms for the new roof. The difiiculty previously encountered in one of the prior art constructions in unscrewing special connectors between the hold-down beams and the corset plates is eliminated.

Tests indicate at least percent of the corset plates and practically all of the hold-down beams are capable of reuse, constituting a great improvement over prior art installations.

In constructing the new roof, once the forms are erected as usual, where forms are to be used, the procedure previously explained is followed, first positioning the basic refractory key or wedge bricks in lateral relation with their hot ends against the forms preferably keying the rings or courses, then placing the corset plates on the cold ends in the correct relationship, with the recesses at the ends allowed to receive the hold-down beams, and then erecting suspended steel structure including the hold-down beams and securing them to the corset plates as previously described. Finally, the hanger connections are made to the hanger tabs or other abutments provided on the refractory brick. Thus, a much easier construction is obtained, with saving of time and cos As compared with both of the prior art roofs referred to, experience indicates that many more heats are obtainable with the roof of the present invention, as well as the other advantages in convenience of its assembly, ease of construction, and reduction of cost per ton of product.

The roof of the invention may be employed in many different variations. It will commonly use magnesia, chrome-magnesia or magnesia-chrome refractory brick of any suitable type as well known in the art of basic refractory roofs.

Of course, the details of the Construction may vary as to whether the roof is used on an open hearth (Siemens) furnace, an electric arc furnace or a reverberatory furnace. In many instances the roof will be rectangular in plan view. In such case, of course, the transverse dimension will be the narrow horizontal dimension and the longitudinal dimension will be the long dimension.

The roof of the invention can also be employed in circular roofs such as those which are used in electric arc steel furnaces, in which case of course one dimension (radial) will be longitudinal and the other at right angles to it will be considered transverse. The invention may also be applied in copper making furnaces, such as copper reverberatory furnaces.

Depending on the roof construction, there may be a hanger connection or tab on each row of bricks, or only on certain rows of bricks, in which case the intervening rows may be held simply by lateral frictional engagement or by lateral interconnection with other bricks (asfrom shoulders).

The actual roof construction in accordance with the invention may involve features of a sprung arch, or it may be wholly suspended or a combination of these aspects. It will be evident that any suitable combination of sprung courses or suspended courses may be used in the present invention, and in a particular suspended course where desired some only rather than all of the bricks may be suspended, as by connecting some only of the tabs to hangers.

The refractory brick themselves may be of any one of a number of shapes, known in the art for example as arch brick, wedge brick, key brick, key-arch brick, keywedge brick, dome brick or otherwise. The choice depends upon the design of the furnace.

The beams which are used as hold-down beams will be I-beams or H-beams and their interconnections to the super-beams may be accomplished in any suitable way, as for example by pipes.

It is important that the corset plates have a con siderable depth of section and also that they be suitably thin, so that they will not interfere seriously with contact between the cold ends of the roof and circulating air above, and will not tend to accumulate dust or dirt that will impair heat transfer. The height of the section should be at least six times its thickness, and in the preferred embodiment will be between six times and twenty-four times the thickness, preferably twelve to twenty times the thickness. The thickness of the corset plates will suitably be in the range from three-eighths to two inches and preferably from one half to one inch, and in the preferred embodiment the height of the corset plates will be in the range of six to twelve inches.

This provides a great depth of section from the standpoint of structural strength and also a great surface to contact the air from the standpoint of cooling the corset plates, so that in this sense they can act like cooling fins.

While the feet may be of solid plate, as shown in one of the forms, they are preferably provided with lateral openings to prevent accumulation of dust. Also to aid in preventing dust accumulation, the feet may clear from the cold ends of the brick until near the outer ends of the feet, and a bearing plate can be provided to secure adequate pressure area in the cold ends. The foot may be cross braced from two corset plates.

The feet will preferably be directly opposite so as not to transmit torsion through the length of the corset plate, and these opposed pairs of feet will preferably be at the middle of the corset plate, although they can be distributed along the corset plates or located near the ends.

It will be evident that the feet from adjoining corset plates must not interfere with one another but must extend out far enough to aid in preventing buckling of the roof. Therefore, there may be an advantage in locating the feet on various corset plates in positions which are not exactly opposite one another.

In some cases the feet will be of unequal length.

Any one of a wide variety of connections may be utilized between the hanger abutments or tabs on the cold ends of the refractory bricks and the corset plates but preferably the connections will be Wire hook connections. It is preferred to use wire hook hangers of the type which can be bent to the correct position over the corset plate at the time of installation.

Considering now the drawings in detail, and referring particularly to the form of FIGURE 1, an open hearth furnace roof is shown being installed according to the invention. For-ms 30, suitably of wood or metal or other material, are provided if forms are used, extending in any suitable shape, usually an arch, between skewbacks 31 at the sides of the furnace (only one is shown). Basic refractory brick 32 are arranged side by side, positioning hot ends 33 against the forms 30, lateral faces 34 in sideby-side relation with other brick (except at the extreme limits of the roof, where they engage adjoining structure such as skewbacks), and cold ends 35 forming a continuous surface at the top. Hanger attachments 36, suitably hanger t-abs on the brick, may initially bend down against the cold ends, or extended, and if lying down are raised for connection with hangers as later to be described.

At suitable positions longitudinally of the furnace chosen so as not to coincide with hanger tabs, corset plates 37 extend in sets across the furnace from skewback to skewback. Each of the corset plates has a relatively long vertical section 38 which may be called the height, and a relatively short thickness 4t) in the longitudinal direction. The plate 37 may desirably be completely rec tangular in vertical cross section except that at opposite ends at the bottom it has small projecting feet 41 engaging the cold ends of the brick and holding the corset plate 37 vertical before the suspended structure has been inserted, and also tending to hold down the adjoining courses of brick.

At each end, where it will abut against or preferably overlap another corset plate, the corset plate 37 has a recess 42 which has at the bottom a suitable flat saddle 43 capable of contacting and supporting the bottom of the hold-down beams to be described. It is preferred to have the saddles overlap as shown so that they will support the hold-down beams in spite of slight variations in relative endwise'position of the corset plates.

The corset plates 37 are positioned so that the recesses 42 are in line longitudinally of the furnace for insertion of hold-down beams. Thus, unlike prior art construction, it is possible to position all of the corset plates in the correct position with the brick already in place, prior to introducing the hold-down beams.

At positions corresponding to the ends of the corset plates, hold-down beams 44 are next inserted resting on the saddle 43 or bottoms of the recesses 42. Each of the hold-down beams is raised above the cold ends of the brick due to the extension of the corset plates at 45 in under the hold-down beams.

It will be evident that in one embodiment the foot 41 protrudes forward from one end of the corset plate and backward from the other end of the corset plate, extending over parts of at least two courses, and that any moment exerted on the corset plate through one of the feet is counteracted by an opposite moment exerted on the corset plate by the opposite foot.

The hold-down beams 44 are connected to and form a part of overhead steel structure 50 including cross binding 51 desirably by pipes 52 extending up from the ends of the hold-down beams and secured as by bolting or by 7 welding to the cross binding. Brackets 53 and bolts 54 secure the pipes 52 to hold-down beams 44.

In order to interconnect the corset plates to one another and to the hold-down beams, tension members 55 are usually carried across and in contact with the tops of the hold-down beams at 56 and anchored at opposite ends by bolts 57 to the corset plates. While the bolts 57 can pass through openings closely engaging the sides of the bolts, the bolts can, where desired, pass through openings which are elongated (slots) to provide some freedom to allow for difference in dimensions of the parts.

Thus, the corset plates are anchored against rising because their extensions 45 rest against the bottoms of the hold-down beams and they are anchored against dropping because the tension members 55 rest on the tops of the hold-down beams 44-.

Other forms of tension members may be used as desired, although the form of FIGURE 1 is preferred. In FIGURE 2 I illustrate tension bars 55 bolted at 57 to the corset plates at the ends and also united at 60 as by welding to the corset plates. In FIGURE 3 the tension bars 55 are united at the ends to the corset plates only by welding at 60. In FIGURE 4 the tension bars 55 are secured at the ends to the corset plates by bending to engage book ends in openings at 58.

In any case the tension members or bars contact the tops of the hold-down beams at 56.

The abutments or tabs 36 of the refractory bricks are interconnected to the tops of the corset plates 37 as for example by using hook hangers 61 which have preferably pre-bent hooks 62 engaging openings in the abutments or tabs 36 and which bend at the top at hook ends 63 over the tops of the corset plates.

Air is preferably provided to circulate laterally against the roof. This is illustrated digrammatically by showing arrows 64 directing the air laterally toward the opposite sides, corresponding to the ultimate direction of air flow from blowers or fans. Once the roof is properly installed, circulating air will in the preferred embodiment continuously or intermittently remove dust and dirt from the cold ends of the brick and prevent excessive accumulation which would otherwise cause localized hot areas.

Once the roof has completed its campaign it is merely necessary to cut the tension members 55 in order to cause the corset plates 37 and the refractory 32 to drop away from the hold-down beams 44, so that the refractory can be separated from the corset plates on the hearth of the furnace or elsewhere and the re-roofing operation as previously described can begin. The hold-down beams and other overhead structure can later be removed as far as necessary to re-roof.

While the various embodiments of the invention offer special advantages for special purposes, the embodiment shown in FIGURE 1 is preferred.

In many cases it will be desirable to provide openings in the feet to permit air to blow away dust accumulations on the ends. In FIGURE 5, feet 41' have lateral openings 65, and are also relieved at 66 so that they engage the coid ends only at 67 near the outer ends. FIGURE 6 shows a variation in which the feet 41 are made of a top bar 68 and a bottom bar 70 at the outer ends supporting steel pads 71 which engage the cold ends of the brick, having lateral openings 65' at the middle and recesses 66' at the bottom.

In FIGURE 7 the foot 41 omits the bottom bar 70 and supports the pad 71 by a top bar 68 from the next corset plate.

In FIGURE 8 the feet 41 have lateral openings 65 and blunted ends 72. They engage the cold ends continuously as they extend outward.

It is preferable to modify FIGURE 1 to locate the feet 41 opposite one another near the center so that no torsional forces need to be transmitted lengthwise of the corset plate 37. In the form shown in FIGURE 9 each foot engages the cold ends of the brick of rows 73, 74

g and 75, to hold the bricks down, but it will be evident that feet of different lengths can be used.

In FIGURE 10 it will be evident that opposite feet 41 are located near the ends of the corset plate and opposite feet 41 are at the middle and are somewhat longer than feet 41 FIGURE 11 shows opposite feet 41 located toward the center with respect to each end and extending out over the cold ends of rows of bricks 73, 74, and 76 to hold them down.

FIGURE 12 shows opposite feet 41 located only near the ends and engaging the cold ends of the brick of two rows 73 and 74.

In FIGURES 13 to 15 comparisons are shown between a fully suspended roof in FIGURE 13, in which the feet 41 engage the cold ends of the bricks of two rows, 73 and 74, and a combination of suspended and sprung arch brick in FIGURES 14 and 15. In each of these views, the feet are shown only at the left, and broken away at the right to show the suspensions.

In FIGURE 14 there are four suspended rows of brick 77, two of which are engaged at the cold end by one foot 41 and then two rows 78 of sprung arch brick supported by the skewbacks. Metallic spacers 80 of inverted channel shape suitably of steel engage the cold ends of the sprung arch brick 78 and also the hold-down beams 44 to hold down the sprung arch brick. It will be evident that the sprung courses can be held down midway between the hold-down beams by a device as in FIGURES 6 or 7.

FIGURE 15 has four rOWs of suspended brick 77 and then four rows of sprung arch brick 78. Feet 41 extend over and hold down two suspended rows and one sprung row. The two intermediate sprung rows are held down by spacer 80.

It will be evident that where the overlapping of the ends of the corset plates occurs under the holddown beams, the hold-down beams are supported on the ends of both of the corset plates, so that the roof is rigid and except for normal expansion and contraction is not free to move up or down during operation.

It will be evident that the invention presents unusual advantages in roofs for special metallurgical furnaces such as electric arc steelmaking furnaces, in which case it will be very convenient to extend the corset plates circumferentially of the roof and also to align the corset plates vertically rather than radially with respect to the roof. This is especially necessary for the newer, larger, and higher-powered electric arc steelmaking furnaces, in which the invention presents unusual advantages. It should be noted that recent attempts to improve such roofs in localized hot spots by putting in panels of basic brick have not been successful because of failure to hold the shape near adjoining areas. The same requirement applies to roofs of electric furnaces entirely conforming to the present invention.

It will further be evident that the brick may be connected to the hanger by a tab, socket, abutment, loop, fitting or other device.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art to obtain all or part of the benefits of my invention Without copying the structure and method shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A refractory furnace roof having a plurality of basic refractory brick arranged side by side, each having a hot end and a cold end and including brick having hanger attachments at the cold ends, ferrous metal corset plates in sets extending transversely of the roof, each set including corset plates in prolongation of one another, in contact with and terminating at the cold ends of the brick and extending above the cold ends of the brick generally at right angles thereto, the corset plates having a height at right angles to the cold ends at least six times their thickness, ferrous metal supporting structure including longitudinal hold-down beams above the cold ends of the brick, fastenings from the ends of the corset plates to the beams to support the corset plates, and hangers from the corset plates to the hanger attachments, in which the corset plates at their opposed ends and remote from the cold ends of the brick have recesses, and the beams extend through the recesses engaging the bottoms thereof and are thereby spaced from the cold ends of the brick.

2. A roof of claim 1, in which the corset plates overlap under the hold-down beams.

3. A roof of claim 1, in which the fastenings comprise tension members extending over the beams in contact with them and secured at the ends to the corset plates.

4. A roof of claim 3, in which said tension members are bars welded at the ends to the corset plates.

5. A roof of claim 4, in combination with means for flowing air against the cold ends in a transverse direction and removing dust from the cold ends.

6. A roof of claim 1, in combination with a foot on each corset plate for supporting the corset plates upright from the cold ends of the brick prior to introduction of the beams and holding down adjoining courses.

7. A roof of claim 6, having opposed feet extending from opposite sides of the same corset plate in contact with the cold ends of the brick.

8. A roof of claim 7, in which pairs of opposed feet are [located at the same position along the length of the plates.

9. A roof of claim 8, in which pairs of opposed feet are located at the middles of corset plates.

10. A roof of claim 8, in which pairs of opposed feet are distributed at a plurality of positions along corset plates.

11. A roof of claim 10, in which the feet are of unequal length.

12. A roof of claim 8, in which pairs of opposed feet are located near opposite ends of corset plates.

13. A roof of claim 6, in which the foot has a lateral opening thereon permitting air circulation.

14; A roof of claim 6, in which the foot engages the cold ends only at points distant from the corset plate.

15. A roof of claim 6, in which the foot includes a bearing plate engaging the cold ends only at points remote from the corset plate.

16. A roof of claim 6, in which the foot includes braces from two adjoining corset plates.

17. A roof of claim 1, in combination with skewbacks at the sides, sprung arch brick interspersed among the brick provided with hanger attachments and supported 10 from the skewbacks, and hold-down beams for preventing the sprung arch brick from rising.

18. A roof of claim 17, in combination with spacers interposed between the cold ends of the sprung arch brick and the hold-down beams.

19. A roof of claim 17, in combination with feet extending from the corset plates and engaging cold ends of the sprung arch brick.

20. A roof of claim 1, in combination with means for blowing air against the cold ends in a transverse direction and removing dust from the cold ends.

21. A process of assembling a basic refractory roof, which comprises erecting forms conforming to the contour of the bottom of the roof, assembling basic refractory brick in side-by-side relation with the hot ends of the brick against the forms and the cold ends of the brick upwardly directed, at least some of the brick having hanger attachments near their cold ends, distributing over the cold ends of the brick corset plates terminating at the cold ends and arranged in sets, the corset plates being relatively thin and relatively deep in vertical section and being supported initially by feet engaging the cold ends, pairs of corset plates in each set being in prolongation of one another and having recesses at their adjoining ends open from above, mounting ferrous metal supporting structure above the roof including lowering hold-down beams into the recesses in the corset plates to rest on the bottoms of the recesses above the cold ends of the brick, cross-connecting adjoining corset plates above the holddown beams and in contact with the hold-down beams, thereby anchoring the corset plates to the hold-down beams against vertical movement either downwardly or upwardly, and connecting the hanger attachments to the upper portions of the corset plates.

22. A process of claim 21, which comprises erecting interspersed among said brick having hanger attachments, sprung arch brick supported by skewbacks, and laying down on the cold ends of said sprung arch brick intermediate the corset plates and in line with the hold-down beams, spacers which engage the hold-down beams and prevent the sprung arch brick from rising.

23. A process of claim 21, which comprises erecting sprung arch brick supported by skewbacks interspersed among said brick having hanger attachments and extending the feet from the corset plates far enough to engage the cold ends of sprung arch brick and prevent them from rising.

References Cited UNITED STATES PATENTS 3,032,327 5/1962 McLain -99 X 3,139,048 6/1964 Hall 110-99 FREDERICK KETTERER, Primary Examiner. 

1. A REFRACTORY FURNACE ROOF HAVING A PLURALITY OF BASIC REFRACTORY BRICK ARRANGED SIDE BY SIDE, HAVING A HOT END AND A COLD END AND INCLUDING BRICK HAVING HANGER ATTACHMENTS AT THE COLD ENDS, FERROUS METAL CORSET PLATES IN SETS EXTENDING TRANSVERSELY OF THE ROOF, EACH SET INCLUDING CORSET PLATES IN PROLONGATION OF ONE ANOTHER, IN CONTACT WITH AND TERMINATING AT THE COLD ENDS OF THE BRICK AND EXTENDING ABOVE THE COLD ENDS OF THE BRICK GENERALLY AT RIGHT ANGLES THERETO, THE CORSET PLATES HAVING A HEIGHT AT RIGHT ANGLES TO THE COLD ENDS AT LEAST SIX TIMES THEIR THICKNESS, FERROUS METAL SUPPORTING STRUCTURE INCLUDING LONGITUDINAL HOLD-DOWN BEAMS ABOVE THE COLD ENDS OF THE BRICK, FASTENINGS FROM THE ENDS OF THE CORSET PLATES TO THE BEAMS TO SUPPORT THE CORSET PLATES, AND HANGERS FROM THE CORSET PLATES TO THE HANGER ATTACHMENTS, IN WHICH THE CORSET PLATES AT THEIR OPPOSED ENDS AND REMOTE FROM THE COLD ENDS OF THE BRICK HAVE RECESSES, AND THE BEAMS EXTEND THROUGH THE RECESSES ENGAGING THE BOTTOMS THEREOF AND ARE THEREBY SPACED FROM THE COLD ENDS OF THE BRICK. 